Take a look at Leo Babuta's Zen Habits site, and you'll know he's a fan of content-focused minimalism. His Gmail web interface is likewise ultra-trim, and he details how to get there with Firefox and some Greasemonkey scripts.

In addition to running a few scripts like Gmail 3: Hide Labels, Chat and Footer, Gmail Remove Stars, and Gmail Real Estate, Leo details the settings and usage required to keep Gmail from becoming unwieldy, at least by his standards. Turn off gadgets, remove unnecessary email "streams" (a good idea for any setup, really), and using Gmail's built-in Tasks to assign emails to actions so they don't sit in the inbox, taking up screen and brain real estate.

Hit the Zen Habits link for a full run-down and before-and-after screenshots, and share your own minimalist Gmail tips in the comments.